Companion planting is based around the idea that certain plants can benefit others when planted next to, or close to one another.

Companion planting exists to benefit certain plants by giving them pest control, naturally without the need to use chemicals, and in some cases they can give a higher crop yield .

Generally, companion planting is thought of as a small-scale gardening practice, but it can be applied on larger-scale operations. It has been proven that by having a beneficial crop in a nearby field that attracts certain insects away from a neighbouring field that has the main crop can prove very beneficial. This action is called trap cropping.

While companion planting has a long history, the benefits of companion planting have not always been understood. Traditional recommendations, for companion planting have been used by gardeners for a long time, but recent tests are proving scientifically, that they work.

Other ways that companion planting can be beneficial is to plant a crop like any Legumes, on an area where it will feed nitrogen into the soil, then it will not be necessary to use any chemical fertilizers for the next crop.

The African marigold, along with other plants, are well known for companion planting, as they exude chemicals from their roots or aerial parts that suppress or repel pests and protect neighbouring plants.

Companion planting also exists in a physical way. For example, tall-growing, sun-loving plants may share space with lower-growing, shade-tolerant species, resulting in higher total yields from the land. This is called spatial interaction, and can also yield pest control benefits, for example, the presence of the prickly vines is said to discourage raccoons from ravaging sweet corn.

Another type of companion planting is called Nurse cropping, where tall or dense-canopied plants may protect more vulnerable plants through shading or by providing a windbreak. For example, oats have long been used to help establish alfalfa and other forages by supplanting the more competitive weeds that would otherwise grow in their place. In many instances, nurse cropping is simply another form of physical-spatial interaction.

Beneficial habitats-sometimes called refugia-are another type of companion planting that has received a lot of attention in recent years. The benefit is derived when companion plants provide a good environment for beneficial insects, and other arthropods, especially those predatory and parasitic species that help to keep pest populations in check.